Frozen food products, such as french fries, are commonly sold in bulk in large bags for heating in a conventional oven. Because of the extended time required for heating frozen food products in a conventional oven, these types of products are generally not practical for a single snack size serving. For this reason, frozen food products capable of being heated in a microwave oven are popular with consumers due to their ease of use, convenience and shorter cooking times as compared to products heated in a conventional oven. Presently available microwaveable products, such as frozen french fries, typically are packaged only in single serving, snack size containers, sold separately from bulk products, for use in conventional ovens. Thus, there remains a need in the art for a product that combines the large serving size of bulk frozen food products with the convenience of microwaveable single snack size products.
However, in order to attain consumer acceptance, microwave cooking must provide food products having sufficient exterior browning and crispness. Frozen food products such as french fried potatoes become soggy when cooked in a paper or cardboard package in a microwave oven due to the generation of steam during cooking. Typical microwave packaging includes a susceptor, a material that absorbs microwave energy and converts it into heat, to cook the food product. A conventional susceptor is usually made of a paper board material laminated or otherwise bonded to a polyester film coated with a metallic layer. The packaging can be made more flexible by laminating the metallized polyester film to paper. To combat the problem of soggy fries, prior art microwave packaging has included vent holes in an effort to allow the steam to escape during heating. Prior art microwave packaging is designed so that the package is laid horizontally on the floor of the microwave oven during cooking.
Attempts have been made to increase the contact between the susceptor and food product to increase browning and crispness by extruding stick shaped food products and surrounding each stick with susceptor material as shown in U.S. Pat. Nos. 4,943,439, 5,034,234, 5,096,723, 5,084,601, and 5,175,404. Although the arrangement shown in these patents improves exterior crispness, the design is expensive to produce and pack, does not allow steam to escape as easily as other prior art designs, and has proven difficult for consumers to remove the stick shaped food product after cooking. Moreover, this design does not allow the use of naturally shaped food products such as random cut french fries.
Despite the developments described above, food products cooked in current microwave packages often come out of the oven limp and soggy. This is due in part to the restrictive horizontal cooking orientation used in prior art packaging. The horizontal cooking orientation provides limp and soggy food products for several reasons. First, juices and oils generated during cooking are not allowed to drain from the product during cooking. Second, when the product is placed in a horizontal orientation, the product is in contact with the floor of the microwave oven which acts as a heat sink, preventing the product from reaching optimal cooking temperature. Third, conventional steam vent holes do not allow all of the steam to escape when the package is oriented horizontally. Finally, the prior art horizontal orientation does not allow for optimum utilization and absorption of the wave pattern of microwave energy during cooking.
Another example of prior art microwave packaging is found in U.S. Pat. Nos. 5,484,984 and 5,543,606. These patents disclose an ovenable food package for holding a food product. The package can be used in the microwave or conventional oven. The base of the package is constructed to include one interior gap between the food product and the base of the package to alleviate the effect of the floor of the microwave oven acting as a heat sink and withdrawing heat away from the food product during heating. Nowhere does the prior art disclose a non-horizontal, angled microwave heating package.
Therefore, it is an object of this invention to provide a microwave heating and/or cooking package that delivers hot, browned and crispy food products from the microwave oven while avoiding the drawbacks associated with the microwave packaging found in the prior art such as the formation of limp and soggy food products. It is another object of this invention to combine the large serving capability of a bulk package of frozen food products with the single serving convenience of a microwaveable package.